The use of clean energy has been increasingly encouraged, and the use of solar cells has been accordingly promoted. A solar cell is generally put into practical use as a solar cell module in which an electromotive element (solar cell) composed of a single-crystalline silicon, silicon-based thin film, a compound semiconductor or the like is sealed with a resin between a surface cover glass and a back cover film. As a structure intended to reduce the cost of the solar cell module, there has been proposed a substrate-integrated thin film-based solar cell module obtained by sequentially forming a transparent electrode layer, a semiconductor layer and a second electrode layer on a transparent insulating substrate, such as glass from the light incident side while patterning the layers using a laser-scribing method.
In recent years, it has been becoming a common practice to mount a solar cell module on the roof of a house or the outer wall of a building in an urban area, and use power generation energy therefrom in the houses or offices. However, it has been pointed out that, when a solar cell module having glass on a surface on the light incident side is installed on the roof or the outer wall, a problem of light pollution may arise in that reflected light from the solar cell module illuminates the interior of the adjacent house depending on an angle of incidence of sunlight, for example.
Thus, an attempt has been made to suppress the glare by forming an irregular shape on the light incident surface of a glass substrate of a solar cell module to irregularly reflect light, and thereby preventing sunlight from being reflected in the same direction. However, for forming an irregular shape on a glass substrate itself, processing at a high temperature or the use of a solution having high reactivity, such as hydrofluoric acid, is necessary, and therefore it is difficult to form irregularities after the modularization of a solar cell. When the glass substrate itself is processed before the modularization, there is the problem in that it is difficult to pattern an electrode layer and a semiconductor layer by laser-scribing because laser light is scattered by the glass substrate.
On the other hand, it has been proposed that, after a solar cell is modularized, an irregularly-shaped film (hereinafter, referred to as an anti-glare film) containing inorganic fine particles in a binder is formed on a glass surface (for example, see Patent Document 1 and Patent Document 2). It has also been proposed that an anti-reflection layer containing spherical inorganic particles having a particle size of 50 to 200 nm in a binder is formed on a glass surface to increase the amount of light captured in a solar cell (for example, see Patent Document 3). These prior art documents propose that a partially hydrolyzed condensate of an alkyl silicate such as tetraethylorthosilicic acid (TEOS) is used as a binder, and spherical silica or the like is used as fine particles.
In addition, a film containing fine particles in an acryl-based or urethane-based organic polymer matrix is formed as an anti-glare film on the surface of a display (for example, see Patent Document 4).